No power, no throttle response, no idle

Discussion in 'Motorized Bicycle Trouble Shooting' started by s1rvr15, Aug 2, 2016.

  1. s1rvr15

    s1rvr15 Member

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    I've searched high and low across the internet, and I cannot for the life of me find a solution to this problem. I have a brand new engine (Flying Horse from Bikeberry), brand new carb, brand new CDI, and brand new spark plug (NGK BPR6HIX), but my motor just does not run right. It starts with no issues whatsoever, but it produces no power (enough to get me going at about 10mph), the throttle does nothing, and if I pull in the clutch it dies. Any input would be great, whether it be a thread I may have missed or some advice.

    Steps I have taken
    -Removed the crappy connectors for the wires and soldered+heat shrunk them
    -Removed the carb air filter and made sure it was clean (and also checked to make sure the throttle was moving the slide inside the carb)
    -Moved the C clip on the jet needle to make it richer and leaner (no change either way)
    -Tried my old spark plug (NGK B6HS gapped to .032")
    -Used gasket sealant on the intake and exhaust gaskets
    -Replaced the fuel filter and fuel line
    -Cleaned the gas tank
    -Tried running it with the gas cap removed (no change)
    -Fiddled with trying to start it with various levels of choke (no changes)
    -Disconnected my kill switch
    -Sanded the back of the magneto loop
    -Resoldered the wire connections on the magneto loop
    -Torqued everything down to within an inch of its life
    -Checked the carb float to make sure it wasn't sunken (it wasn't)
     
  2. Tyler6357

    Tyler6357 Well-Known Member

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    "-Torqued everything down to within an inch of its life"

    What about the head studs? Are you using the acorn nuts? If so, you should get rid of them and get quality nuts from the hardware store. They are known for bottoming out on the studs and continued tightening will strip the threads. Tighten head nuts down to 120 to 140 INCH pounds. If you got them torqued correctly and the problem isn't solved, it sounds like you have an air leak. Start the engine and feel around the head for any air shooting out from around the head gasket, you might have blown the head gasket or just have a leak. Also, check for air leaks around the intake manifold and carb connections. Loss of power is usually caused by loss of compression or an air leak.

    brnot
     
    #2 Tyler6357, Aug 3, 2016
    Last edited: Aug 3, 2016
  3. s1rvr15

    s1rvr15 Member

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    My biggest problem is that I can't stop it to try and troubleshoot it. If I pull in the clutch to put down the kickstand and start looking for air leaks, the engine dies instantly.
     
  4. crassius

    crassius Well-Known Member

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    whenever a carb adjustment has no effect, I start looking for a fuel starvation condition - open drain plug & check flow thru bowl, check main jet and needle jet tube, check the 'feel' of the carb seat as you put it on the intake (even sliding action with no wobble)

    had one once where the customer put slide in upside down (was shocked it even started when I saw that)
     
  5. s1rvr15

    s1rvr15 Member

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    The jet is clear, and the bowl is full of fuel, the slide is in the right way (the end of the idle screw sits on the larger cutout in the slide), and the carb sits solidly on the manifold. If I ride it as if I'm trying to start it with the spark plug boot off, the plug gets nice and wet with fuel, so the cylinder has to be getting gas. One thing I do notice is that it produces a whole lot more smoke than my old one (using literally the same gas), to the point that I'm thinking there's too much oil in my fuel for it to run right; could that be an issue?
     
  6. crassius

    crassius Well-Known Member

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    too much smoke often means a motor full of fuel - either just keep pedaling to help it along till it clears, or unplug power wire to CDI and take out plug and pedal a lot to blow it out

    also, loosening muffler just 1/8th on an inch will help if muffler cap is full of fuel
     
  7. s1rvr15

    s1rvr15 Member

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    Thanks for the idea! Unfortunately the sky just opened up so I can't exactly work on that, but could the motor being full of fuel cause my lack of power and throttle response?
     
  8. crassius

    crassius Well-Known Member

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    certainly - may have to run several miles before getting power back if fuel was fresh and will burn well

    got one here at shop sat 8 months with fuel in motor - gas evaporated leaving motor full of sticky oil - 30 miles running to get full speed, but still weak uphill - may be a long time yet to clean that out
     
  9. Tyler6357

    Tyler6357 Well-Known Member

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    Possibly you can reach down and feel around the head while you are riding, or else, try shining a flash light on one side of the head and see if you can see any light shining through from the other side. Remove the head and see if you can see any signs of a leak, a dark or blackened area on the head or gasket. Stock heads are notorious for leaking on these little engines.
     
  10. s1rvr15

    s1rvr15 Member

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    I shined my 700 lumen headlight into the spark plug hole, and could not find any place where I could see any light shining through around any point on the engine. No signs of oil or any other dark residue on the outside of the engine whatsoever.
     
  11. Tyler6357

    Tyler6357 Well-Known Member

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    Well, the spark plug hole might not shine enough light to see a leak because of the angle. Another thought, you could spray some water around the head and gasket connection and then start the motor and see if you can see or feel if any of the water blows out.
     
  12. s1rvr15

    s1rvr15 Member

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    I'm gonna give that a shot when I get time to tinker with it tomorrow, thank you!
     
  13. Tyler6357

    Tyler6357 Well-Known Member

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    You could use soapy water so you can see it better.
     
  14. 2door

    2door Moderator
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    From your description it doesn't sound like the engine is running at all.

    If your plug is wet then you're getting fuel to the combustion chamber. I believe you're having ignition problems. You haven't mentioned if, or how you've checked that.

    Here's a good guide to follow if the engine doesn't start> http://motorbicycling.com/showthread.php?t=35090

    Tom
     
  15. s1rvr15

    s1rvr15 Member

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    It starts, but it doesn't. It does turn over, but it won't rev whatsoever, and taking the load off the engine and pulling in the clutch kills it; I can get maybe 20 feet out of it without it dying, which sounds like intermittent spark to me.

    All the resistance readings are normal (within a few Ohms or so of the values on the page), perhaps my solder joints are just bad and aren't working as they should? I can cut off the heat shrink and take pictures of those if any of you can tell me if they're bad (I haven't done much soldering in my time). As for the wires, I replaced what I could with 16 gauge copper wire. I have also tried disconnecting my kill switch (a key switch I picked up from the local auto parts store), which also does nothing. I made a quick and dirty "schematic" of my wiring, if there's anything wrong with the way I have wired things.

    [​IMG]
     
  16. 2door

    2door Moderator
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    That won't work. If your wiring is as pictured the blue wire never connects the CDI and magneto. Get rid of that switch you're using. You want the blue wire and black wire from the CDI to connect to the blue and black from the magneto. A kill switch is a normally open, momentary contact that connects those two wires when depressed.

    Disconnect the switch and wire the blue and black directly to each other and give it a try. Let us know what happens.

    You still haven't told us how you are confirming that you're getting spark at the plug.

    To do this you need to remove the plug from the head, connect the spark plug wire, lay the plug against the engine and spin the rear wheel with the clutch engaged. It needs to spin fast and in a darkened area where you can see a spark at the plug's electrode.

    If you're using the kit supplied spark plug boot that might be part of your problem. They are notorious for bad connections. Replace it with an automotive quality boot and one that will work with a spark plug with the top cap installed. If you're using the kit boot with a plug that still has the cap, that's your problem. The kit boot requires that the cap be removed. Otherwise the boot cannot make correct contact. Poor, poor design and one that has caused many problems with these kits.

    Tom
     
    #16 2door, Aug 4, 2016
    Last edited: Aug 4, 2016
  17. s1rvr15

    s1rvr15 Member

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    There are two ways I know it is at least sparking some of the time: the method you mentioned of putting the plug against the head and spinning the wheel, and the fact that the bike starts for 10-20 seconds at a time. I'll disconnect my switch and see how it goes.
     
  18. crassius

    crassius Well-Known Member

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    also, try to keep pedaling to keep it going for a longer time
     
  19. s1rvr15

    s1rvr15 Member

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    No joy as far as pedaling it to keep it going goes, unfortunately. Both the exhaust and the bottom of the engine are dripping oil, though.
     

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